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https://issues.apache.org/jira/browse/FLINK-5266?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15734203#comment-15734203
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ASF GitHub Bot commented on FLINK-5266:
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Github user KurtYoung commented on the issue:
https://github.com/apache/flink/pull/2961
rebased to latest master
> Eagerly project unused fields when selecting aggregation fields
> ---------------------------------------------------------------
>
> Key: FLINK-5266
> URL: https://issues.apache.org/jira/browse/FLINK-5266
> Project: Flink
> Issue Type: Improvement
> Components: Table API & SQL
> Reporter: Kurt Young
> Assignee: Kurt Young
>
> When we call table's {{select}} method and if it contains some aggregations,
> we will project fields after the aggregation. Would be better to project
> unused fields before the aggregation, and can furthermore leave the
> opportunity to push the project into scan.
> For example, the current logical plan of a simple query:
> {code}
> table.select('a.sum as 's, 'a.max)
> {code}
> is
> {code}
> LogicalProject(s=[$0], TMP_2=[$1])
> LogicalAggregate(group=[{}], TMP_0=[SUM($5)], TMP_1=[MAX($5)])
> LogicalTableScan(table=[[supplier]])
> {code}
> Would be better if we can project unused fields right after scan, and looks
> like this:
> {code}
> LogicalProject(s=[$0], EXPR$1=[$0])
> LogicalAggregate(group=[{}], EXPR$1=[SUM($0)])
> LogicalProject(a=[$5])
> LogicalTableScan(table=[[supplier]])
> {code}
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